Electrical air-heater.



F. KUHN & I. A. HAND. ELECTRICAL AIR HEATER.

APPLICATION FILED FEB. ZI, I918.

1,279,363 I Patented Sept. 17,1918

Fra/n/fi Ilia/kn Jay A. flan/d UNITED STATES PATENT OFFICE.

FRANK KUHN AND JAY 1L HAND, OF DETROIT, MICHIGAN. ASSIGNORS TO AMERICAN ELECTRICAL HEATER COMPANY, OF DETROIT, MICImiGAN, A CORPORATION OF MICHIGAN.

ELECTRICAL AIR-HEATER.

Specification of Letters Patent. Patented Sepia 1'7, 1918- Application filed February 21. 1918. Serial No. 218,397.

gan, have invented certain new and useful Improvements in Electrical Air-Heaters, of which the following 'is a specification, reference being had therein to the accompanying drawings. I

The invention'relates to electric heaters more particularly designed for use in preventing freezing or undesirably low temperatures, as for instance to be used under the hood of an automobile when standing in a cold garage. The invention comprises the novel construction as hereinafterset forth. a

In the drawings: 7

Figure 1 is a perspective View of the device having a portion of the casing broken away; and

Fig. 2 is a vertical longitudinal section thereof. c p It is the object of the invention to obtain an exceedingly simple and inexpensive construction which may be conveniently placed under the hood of the automobile or for other similar purposes and which is effectually, protected from overheating, or the rise in temperature of any part to adangerous degree. Particularly for use in connection with automobiles it is desirable to avoid a temperature which might ignite inflammable. gas or vapor and at the same .time it is neces sary to have sufiicient heat generation to properly modify the temperature of the ma- This we have accomplished by the following construction.

A is an insulator rod or core, preferably a tube of porcelain or similar insulating material, and B is a resistor wound about said core and which, to obtain the desired high resistance, is formed of a spirally coiled wire wound in a larger spiral around the tube. The ends of the coil are secured in position and are electrically connected to terminal conductors by suitable means, such as the clamps C at the opposite ends of the core, said clamps also engaging the ends of the terminal conductors D. E is a protecting casing, which is preferably formed of rectangular flanged heads F and a rectangularbody G fashioned from perforated sheetsmall which is metal. The flanges .of the heads F overlap the ends of the perforated body G, and the heads are secured by a tie-bolt H extending centrally through the tube A and having a clamping nut I at its opposite end. J is an insulator bushing engaging an aperture in one of the headsF, through which the flexible conductor is passed, said bushing being secured by a spring clamping member K engaging a shank on the inner side of the head.

The flexible conductor, after passing outthrough the bushing, is connected to the head F by aclipL which is secured by the bolt H.

With the construction as described it will be noted that the resistor is exposed to free contact with the air on all sides and is also protected from contact with any body which might shield its radiation by close contact therewith. Thus if the resistance of the resistoris properly proportioned the current passing therethrough willnot raise any portion to a temperature which will ignite inflammable-gas or vapor. This is true whether the device is in service for a long time or a short period of time, as the rate of heat dissipation from all portions of the resistor is sufficient to prevent an undesirable rise in temperature.

It will be appreciated that the device so I constructed may be employed with perfect safety, whereas any construction in which there is a part of the resistor, no matter how protected from heat dissipation will be asource of danger.

\Vhat we claim as our invention is:

1. An electrical heater, comprising a tubular insulator core, a resistor formed of a" coiled wire wound spirally about said core, clamps engaging sald core at the opposite ends thereof and forming terminals for said resistor, heads at opposite ends of said core, a perforated body between said heads and spaced uniformly from said resistor on opposite sides thereof, an insulator bushing passing through one of said heads, a conductor connected to said resistor and passing outward through said bushing, a bolt passing through said hollow core for holding the same and clamping said heads, and a clip secured by said bolt for holding the conductor passing outward through said bushing.

2. In an electrical heater, the combination for engagement with said resistor, and a, with an insulator core, and a resistor wound spring clamping member for retaining said about said core, of a casing having heads at insulator bushing in place. opposite ends of said core, a perforated body In testimony whereof We afiix our signa- 5 between said heads forming equal air spaces tures.

on opposite sides of the core, an insulator i FRANK KUHN. bushing passing through one of said heads, J AY A. HAND. 

